The leukotrienes and their biological activities, especially their roles in various disease states and conditions have been described. For example, see U.S. Pat. No. 4,683,325 (Jul. 28, 1987), which is incorporated herein by reference.
Several classes of compounds exhibit the ability to inhibit the biosynthesis of leukotrienes in mammals, especially humans. For example, EP 349,062 (Merck) describes a series of compounds of the general formula A: ##STR2##
EP 339,416 (Bayer) and 344, 519 (Bayer) describe compounds of Formulas B and C respectively: ##STR3##
The above compounds differ chemically from the present invention in a major structural feature. Namely, the compounds of the present invention contain a tetrahydrocarbazole nucleus, which is absent from the above.
Compounds D, E, F and G, containing tetrahydrocarbazole structures, are described in U.S. Pat. Nos. 4,578,398 (AHP), 4,057,559 (AHP), and 4,808,608 (Merck), and U.K. 1,382,513 (Roche) as having various biological activities. However, none of these compounds contain a quinoline nucleus joined to the tetrahydrocarbazole moiety, and such a major change would not obviously give rise to any particularly useful biological activity. ##STR4##